Certainly Allah was well pleased with the believers when they swore allegiance to you under the tree, and He knew what was in their hearts, so He sent down tranquillity on them and rewarded them with a near victory,

Then We made Our messengers to follow in their footsteps, and We sent Isa son of Marium afterwards, and We gave him the Injeel, and We put in the hearts of those who followed him kindness and mercy; and (as for) monkery, they innovated it-- We did not prescribe it to them-- only to seek Allah's pleasure, but they did not observe it with its due observance; so We gave to those of them who believed their reward, and most of them are transgressors.

You shall not find a people who believe in Allah and the latter day befriending those who act in opposition to Allah and His Messenger, even though they were their (own) fathers, or their sons, or their brothers, or their kinsfolk; these are they into whose hearts He has impressed faith, and whom He has strengthened with an inspiration from Him: and He will cause them to enter gardens beneath which rivers flow, abiding therein; Allah is well-pleased with them and they are well-pleased with Him these are Allah's party: now surely the party of Allah are the successful ones.